Ascension Seton researcher develops breakthrough antidote drug

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Investigational drug could save lives of patients with life-threatening bleeding from popular blood thinners

An Ascension Seton researcher has helped develop an investigational new drug that works as an antidote to the most popular new class of blood thinners – and, if approved, could be a potentially life-saving therapy for patients taking blood thinners who experience life-threatening bleeding, according to new interim results from an ongoing clinical trial.

The interim results, published in the New England Journal of Medicine, show that the novel drug andexanet alfa can restore normal blood clotting in people taking blood thinners known as Factor Xa inhibitors. Andexanet alfa works as an antidote for bleeding patients taking those blood thinners.

“Currently, we have no way to turn off the anticoagulant action of these blood thinner drugs. Given these promising study findings,  if you were in a car wreck and severely injured while taking a blood thinner, this could be the answer to help prevent you from bleeding out, if the drug is approved by the FDA,” said study author Truman Milling, Jr., MD, of Ascension Seton Dell Medical School Stroke Institute and The University of Texas at Austin Dell Medical School. Ascension Seton is part of Ascension, the largest nonprofit health system in the U.S.TJ Milling small

Because of the critical need for this type of an antidote, the FDA gave andexanet alfa a “breakthrough therapy” designation, allowing the drug maker to apply for approval to market the drug even before this clinical trial is over. The treatment could be available to the public next year.

Examples of blood thinners for which  andexanet alfa reverses the anticoagulation activity  are rivaroxaban (“Xarelto”), apixaban (“Eliquis”), edoxaban (“Savaysa”) and enoxaparin (“Lovenox”).

Study findings were presented today at the European Society of Cardiology in Rome. The interim results from 67 participants taking  rivaroxaban,  apixaban or enoxaparin and suffering from major gastrointestinal or brain bleeding showed:

  • Andexanet alfa was associated with about a 90 percent decrease in anticoagulation, meaning it significantly reversed the blood thinning action of the Factor Xa inhibitors.
  • Normal blood clotting was restored in about 81 percent of patients.

Factor Xa inhibitors are critical in helping prevent strokes and blood clots in the legs or lungs. They are most commonly taken by patients with an irregular heartbeat, and those who are prone to deep vein thrombosis or pulmonary embolism (blood clots in the lungs).

However, these blood thinners can cause serious bleeding problems if a patient suffers an injury or has a bleeding stomach ulcer, because they reduce the ability of blood to clot.

“Strokes are devastating and lethal and often debilitating. If you’re prone to clots, a blood thinner can reduce your risk of stroke by about two-thirds. But when you do bleed, it’s important to have a way to turn the blood thinners off,” Milling said.

Andexanet alfa works as a decoy. It “fools” Factor Xa inhibitors into binding to it. As a result, the blood thinner isn’t able to work properly and the blood can coagulate again.

Andexanet alfa is being developed by Portola Pharmaceuticals, Inc. under the brand name AndexXa.™ Milling received a research honorarium from the Public Health Research Institute.